<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    
</body>
<script>
    var str="赵钱孙李 周吴郑王";
    var index=str.indexOf("孙");
    var index1=str.indexOf("周");
    /*str,slice(start,end)
    start索引位置是包含的
    end不包含
    */
    var child=str.slice(index+1,index1);
    console.log(child);
    
</script>
</html>